Dozens of shipping containers tumbled over the side of a cargo ship and into the water Tuesday at the Port of Long Beach.

It was not immediately clear what was in the containers, which were stacked on the Mississippi cargo ship at a dock around 9 a.m. when they toppled over the side of the vessel, port officials said. There were no immediate reports of injuries.

The U.S. Coast Guard, which responded to the scene near the port’s Pier G, said nearly 70 containers were in the water. Boxes and other other items were floating alongside the containers.

The container ship arrived in Long Beach Tuesday morning.

Cargo operations were temporarily suspended at the terminal as responders worked to secure the containers, said Port of Long Beach spokesperson Art Marroquin. Authorities are attempting to determine what caused the mishap, Marroquin said.

Crews appeared to be spraying high-pressure water to keep the cargo from floating out to sea.

The port is the U.S. gateway for Pacific trade and handled more than 9.6 million container units in 2024, its busiest year in history.